1. Field of the Invention
The present invention relates to a laser surveying device which rotates a laser head to project a laser beam around.
2. Description of the Related Art
In related art Japanese Patent Application Publication No. 2007-271627 discloses a laser surveying device comprises a rotatable, tiltable laser head in a housing, to rotate the laser head to project a laser beam around, for example.
Such a laser surveying device comprises a laser projector tiltable relative to the housing and projecting a laser beam upward, a laser head rotatably provided above the laser projector, a first tilt sensor to detect a tilt angle of the laser projector in X direction, a second tilt sensor to detect a tilt angle of the laser projector in Y direction, a tilt mechanism to tilt the laser projector to be vertical on the basis of a result of the first and second tilt sensors, and a cover glass provided above the housing to cover the laser head.
The laser projector is controlled to be vertically directed by the tilt mechanism on the basis of a result of the first and second tilt sensors. Along with the rotation of the laser head, the laser beam is projected around from the laser projector via the cover glass.
The laser surveying device includes four columns to support the cover glass. However, these columns may disadvantageously block the laser beam and deform the profile of the laser beam, which results in decreasing surveying accuracy in the area in which the laser beam is blocked by the columns. In view of this, the laser surveying device is configured to stop projecting a laser beam in this area. When the laser projector in rotation does not tilt at all relative to the housing, the area in which beam projection is stopped can be narrow. However, the larger the tilt of the laser projector is, the wider the area is.
The beam projection stop area is set to be wide in accordance with an assumed maximal tilt for the purpose of preventing a decrease in surveying accuracy without a tilt sensor for the laser head relative to the housing. This leads to unnecessarily narrowing the surveying area illuminated with the laser beam, even when the tilt angle of the laser projector relative to the housing is zero.